This is unethical, basically he calls for jumping off of flights at layovers, which violates the terms of the ticket. There's even a security issue for the airlines, because they need to check if your bags are flying unaccompanied. Ironic that the NYT cracks down on people evading its paywall but is selling content on doing the same for air travel.
"they need to check if your bags are flying unaccompanied" For those traveling with checked luggage, this "hop off" tactic won't work, unless passengers want to lose their bags. For those without checked luggage, the airlines have no way of determining whether your carry-on bags are still on the plane or not, short of emptying the plane and reboarding (which I have never seen before).
* Yes, I'm aware this is a cognitive bias. http://en.wikipedia.org/wiki/Availability_heuristic